I can’t answer, but here are some URLs you might find useful despite being centered on x86:
http://x86asm.net/articles/uefi-programming-first-steps/
https://www.uefi.org/specifications
NVIDIA uses edk2 release. See:
https://github.com/tianocore/tianocore.github.io/wiki/EDK-II
https://github.com/NVIDIA/edk2
Should you be working with stages past the hardware firmware abstraction it should be possible to work with UEFI on the Jetsons the same way you’d work with a PC’s UEFI.